Effect of Atmospheric Pressure Plasma in Inert Gases on Orthopedic Ultra-High Molecular Weight Polyethylene

Abstract

In this work, studies have been conducted on the treatment of ultrahigh molecular weight polyethylene (UHMWPE), which is one of the structural materials used in the endoprostheses, with atmospheric pressure plasma in high-purity argon and helium. For this purpose, an installation consisting of a high-voltage pulsed generator, voltage and current measuring devices and a reaction quartz chamber with electrodes, in which UHMWPE samples were placed, was developed and constructed. It is shown that processing under certain conditions in Ar plasma and He at atmospheric pressure leads to the appearance of terminal double bonds in the structure of the processed polyethylene, as evidenced by the appearance of a peak of 880 cm-1, in the attenuated total reflection IR spectrum. This peak is observed both for samples treated in helium and argon plasma. The formation of such bonds is a consequence of the generation of active radicals in the UHMWPE surface layer under plasma treatment, which, during recombination, also form intermolecular crosslinking, thereby increasing the strength characteristics of the material as a whole. The modification of the surface of the treated samples begins within the first minute of processing and reaches its peak values 10-20 minutes after treatment in plasma.